![]() Shrock Professor of Geology in MIT’s Department of Earth, Atmospheric and Planetary Sciences. ![]() He surmised that the root cause of mass extinctions might be a shorter, more specific interval of magmatism within the much longer period over which large igneous provinces form.īurgess decided to re-examine geochronologic measurements he made as a graduate student in the lab of Samuel Bowring, the Robert R. That told me that it’s not the entire large igneous province driving extinction,” says Burgess, who is now a research scientist for the U.S. “One thing really stuck out as a sore thumb to me: The total duration of magmatism in most cases is about 1 million years, but extinctions happen really quickly, in about 10,000 years. But Burgess was struck by a certain incongruity in such hypotheses. Since the 1980s, scientists have suspected that the Earth’s most severe extinction events, the end-Permian included, were triggered by large igneous provinces such as the Siberian Traps - expansive accumulations of igneous rock, formed from protracted eruptions of lava over land and intrusions of magma beneath the surface. ![]() And we think the smoking gun is the first pulse of Siberian Traps sills.” “Gases warmed the climate, acidified the ocean, and made it very difficult for things on land and in the ocean to survive. “This first pulse of sills generated a huge volume of greenhouse gases, and things got really bad, really fast,” says first author and former MIT graduate student Seth Burgess. Some of this molten liquid stopped short of erupting onto the surface and instead spread out beneath the Earth’s shallow crust, creating a vast network of rock stretching across almost 1 million square miles.Īs the subsurface magma crystallized into geologic formations called sills, it heated the surrounding carbon-rich sediments and rapidly released into the atmosphere a tremendous volume of carbon dioxide, methane, and other greenhouse gases. In a paper published today in Nature Communications, the team reports that about 251.9 million years ago, a huge pulse of magma rose up through the Earth, in a region that today is known as the Siberian Traps. Geological Survey and MIT have homed in on the precise event that set off the end-Permian extinction, Earth’s most devastating mass extinction, which killed off 90 percent of marine organisms and 75 percent of life on land approximately 252 million years ago.
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